The analysis of the lex mercatoria is of interest not only to the topic’s present aspect, but also to its historical roots. Within the framework of an analytical effort shared on the one hand by historians and on the other by lawyers and sociologists alert to current developments, there is one aspect that deserves everyone’s attention: the understanding of the differences between the phenomenon as it is today and the phenomenon as it was in the past. As a matter of fact, apparent similarities conceal not only a new lex mercatoria that is profoundly changed in itself, but also in a very different institutional, social and economic scenario. The rise of the lex mercatoria in the present day implies a challenge to the state. The new ‘Law Merchant’ completely escapes the traditional connotations of class, developing into a law with extensive repercussions that no longer acknowledge any geographical boundaries. This throws light on a paradox of the globalised world, in which laws and legislators are losing ground at the same time as vitality is regained by expressions of law in the singular that flow in the channels of universalism, crossing every territorial and cultural border.